How to set off background color reflection?
You Don't have to use chroma,You can just render the video in alpha channel.

Cycles:



To do so,You just have to check transparent  film panel:


This will render the background as Alpha but the reflections will be still here.

To remove the colored reflection,Uncheck use Environment in render layer:



Blender Internal:



You just have to Uncheck Sky in render layers: